4 if you have the room, I only lost 1C going from push pull to pull only, but I am running an RX360mm on just my CPU.(GPU has a kuhler 620 on it)

incidentally I have version 4 installed because somehow it made more sense to me originally. and yes, after removing the coolermaster V8, I now have oodles of room. I could fit a horse in there now, and still have room for a zebra.